Send-PnPMail within Azure Function

[HeKr09]

I have got an Azure Function that currently sends an email by using Send-PnPMail. The function logs on with a managed identity. Everything works fine.

Now there is the requirement to send with a high importance. This can only be done by using the from parameter.
But when I specify the from parameter differently than the logged in user I get an access denied error. If I log on as the user who should send the mail the error disappears.

1. Is it possible to send from another mail than the one that is logged on by Connect-PnPOnline
2. Is it possible to connect with Connect-PnPOnline within an Azure Function with another user? (without storing the credentials!)